I think the base idea is promising, however. First thing would be long slow build up being required. skipping ahead a few weeks to the point your SI isn't scrounging for basic parts and tools is fine, but yeah, slow build.
Your SI kissed Taylor on the cheek.... SI starts dating canon protagonist is usually a bad choice if for no other reason then it usually happens by mangling the canon personality. Procede with extreme caution.
Finally the way you plot progressed to all out war in the streets. No, bad author. If you want to kill tbe villians because fuck the villians and the three strikes rule then you don't need to release their identities and claim responsibility or any of that.
Just summon a fate assassin, stage a bunch of fake drive by shootings, snipe the fuckers, blow up the gangs storehouses with the capes inside them. Mix up your methods but keep going for that end result.
Yes having stupid amounts of power is very nice and makes hitting the problem like a sledge hammer seam appealing but even the venear of subtlety when killing a few dozen super powered criminal crazies would be a good idea.
Sure everyone will know, but they won't be able to prove it. Besides which Brockton Bay is Cauldron's test bed. They keep their hands off of it. So as long as you aren't demanding a spot in the national news proclaiming what you did, why, and to whom, odds are they won't act.
